Vector analysis of astigmatism correction after PRK, FS-LASIK, and SMILE for myopic astigmatism.

PURPOSE: To compare astigmatic correction among photorefractive keratectomy (PRK), femtosecond laser-assisted in situ keratomileusis (FS-LASIK), and small-incision lenticule extraction (SMILE). METHODS: This prospective study enrolled 157 eyes that underwent three procedures (59 PRK, 47 FS-LASIK, and 51 SMILE) for the treatment of myopia with low to high astigmatism (- 0.25 to - 4.50 D). Ocular residual astigmatism (ORA) was calculated by vector analysis using refractive (RA) and corneal astigmatism. Vector analysis results were compared in different procedures in the two RA groups (low ≤ 1.00 D and high > 1.00 D) at 3 and 12 months postoperatively. RESULTS: There were no significant between-group differences in postoperative safety and efficacy outcomes (all P > 0.05). No significant differences were found in postoperative cylinders between all surgical groups (all p > 0.05), except for 3 months postoperative ORA in FS-LASIK (P = 0.004). At 12 months, 77%, 59.2%, and 50% of eyes attain emmetropia in the FS-LASIK, SMILE, and PRK groups, respectively. Vector analysis showed comparable values for surgical induced astigmatism, target induced astigmatism, mean error, and angle of error between groups at 12 months. Significant differences were observed only in the correction index and difference vector parameters in the astigmatic > 1.00 D group at 3 months (P < 0.001), and FS-LASIK was preferable. CONCLUSIONS: One-year outcomes revealed that PRK, FS-LASIK, and SMILE were all equally effective in correcting myopic astigmatism. However, FS-LASIK demonstrated more favorable astigmatism correction in eyes with astigmatism > 1.00D in early postoperatively.

Femtosecond laser-assisted laser in situ keratomileusis for the correction of high myopia in Meesmann corneal dystrophy: a case report / Femto-LASIK para correção de alta miopia na distrofa corneana de Meesmann: relato de caso

ABSTRACT The patient was a 26-year-old woman who had manifest refraction and uncorrected and corrected distance visual acuities of -7.00 × -4.50 at 175°, 20/400, and 20/25, respectively, in the right eye, and -3.25 × -5.25 at 179°, 20/200, and 20/25, respectively, in the left eye. In the right and left eyes, the mean corneal thicknesses were 733 and 749 µm, and the maximum epithelial thicknesses were 70 and 68 µm, respectively. Myriads of intraepithelial cysts were observed in the slit-lamp examination. At 30 months after femtosecond laser-assisted laser in situ keratomileusis (femto-LASIK), the manifest refraction and uncorrected and corrected distance visual acuities were respectively 0.00 × -1.25 at 55°, 20/25, and 20/20 in right eye, and 0.00 × -0.50 at 135°, 20/20, and 20/20 in the left eye. In this case of Meesmann dystrophy, myopia was successfully treated with thick flap femto-LASIK without complications or ectasia.

RESUMO A paciente era uma mulher de 26 anos com refração manifesta, acuidade visual para longe não corrigida e corrigida de -7,00 × -4,50 a175°, 20/400 e 20/25 no olho direito e -3,25 × -5,25 a 179°, 20/200 e 20/25 no olho esquerdo. A espessura média da córnea foi de 733 e 749 µm, e a espessura epitelial máxima foi de 70 e 68 µm, respectivamente no olho direito e no esquerdo. Inúmeros cistos intraepiteliais foram observados no exame com lâmpada de fenda. Trinta meses após o femto-LASIK, a refração manifesta, a acuidade visual para longe não corrigida e corrigida eram respectivamente de 0,00 × -1,25 a 55°, 20/25 e 20/20 no olho direito e 0,00 × -0,50 a 135°, 20/20 e 20/20 no olho esquerdo. Neste caso de distrofia de Meesmann, a miopia foi tratada com sucesso com femto-LASIK de retalho espesso sem complicações ou ectasia.

Variability of CLMI-X parameters, zonal Kmax, and single-point Kmax in keratoconus progression.

OBJECTIVES: To compare the repeatability of Cone Location and Magnitude Index expanded (CLMI.X) parameters of 2 mm diameter zone of greatest corneal curvature (Cspot-Axi) and 1 mm diameter zone of thinnest pachmymetry (Spot-Pach) with the maximum single point keratometry (Kmax), 3 mm Zonal Kmax (Z-Kmax3), and thinnest single point pachymetry (TP) in keratoconus (KC). METHODS: In this Comparative repeatability study, data from 36 eyes of 36 normal individuals and 72 eyes of 72 KC patients (28 eyes with ≤50.0D and 44 eyes with >50.0D Z-Kmax3) were analyzed. For each enrolled eye, imaging was done 6 times (3 consecutive acquisitions with a half hour break). For each parameter, the within-subject standard deviation (Sw) was calculated from the data of the six exams. RESULTS: In the normal group, Cspot-Axi-Sw was different from Kmax-Sw (p = 0.0004). Also, Z-Kmax3-Sw was different from Kmax-Sw (p = 0.0297). The difference between Cspot-Axi-Sw and Z-Kmax3-Sw was statistically significant (p = 0.0482). In the KC group, Sw were significantly different between Cspot-Axi and Kmax (p < 0.0001), and between Z-Kmax3 and Kmax (p < 0.0001). In the Z-Kmax3 ≤ 50.0D subgroup, Sw were different between Cspot-Axi and Kmax (p = 0.0002). In the Z-Kmax3 > 50.0D subgroup, Sw were different between Cspot-Axi and Kmax (p < 0.0001), and between Z-Kmax3 and Kmax (p < 0.0001). Sw differences between Spot-Pach and TP were not significant in any of the study groups (all P > 0.05). CONCLUSIONS: In the diagnosis and follow up of KC, the zonal averages of Cspot-Axi and Z-Kmax3 are more reliable than the single point Kmax. The repeatability of Spot-Pach is similar to TP and both variables should suit the purpose equally.

Corneal Biomechanics After SMILE, Femtosecond-Assisted LASIK, and Photorefractive Keratectomy: A Matched Comparison Study.

Purpose: To evaluate the change in corneal stiffness after small incision lenticule extraction (SMILE), femtosecond laser-assisted in situ keratomileusis (FS-LASIK), and photorefractive keratectomy (PRK). Methods: Age, gender, spherical equivalent, and central corneal thickness (CCT)-matched cases undergoing SMILE with a 120-µ cap, FS-LASIK with a 110-µ flap, and PRK were enrolled. One-year change in the stress-strain index, stiffness parameter at first applanation, integrated inverse radius, deformation amplitude ratio at 2 mm, and deformation amplitude ratio at 1 mm were compared between the surgical groups by linear mixed-effect models. Results: Within each surgical group, 120 eyes completed 1 year of follow-up. The residual stromal bed (RSB) thickness and (RSB/CCTpostop) were 348.1 ± 35.0 (0.74), 375.4 ± 31.0 (0.77) and 426.7 ± 2 µm (0.88) after SMILE, FS-LASIK, and PRK, respectively. The 1-year change in all biomechanical indices was significant, except the stress-strain index with PRK (P = 0.884). The change in all indices with SMILE were significantly greater than with FS-LASIK and with PRK (all P < 0.01), except the deformation amplitude ratio at 1 mm change between SMILE and FS-LASIK (P = 0.075). The changes in all indices with FS-LASIK were significantly greater than with PRK (all P < 0.05). Conclusions: Although SMILE preserves the greatest amount of anterior cornea with a cap thickness of 120 µ, this also produces the smallest RSB and the greatest decrease in stiffness. Thus, the RSB is shown to be the predominant determinant of stiffness decreases, rather than the preserved anterior cornea. We recommend using a thinner cap to achieve a thicker RSB and a lesser decrease in the corneal stiffness in the SMILE procedure. Translational Relevance: After refractive surgery, RSB is predominant determinant of stiffness decreases, rather than the preserved anterior cornea.

Femtosecond laser-assisted laser in situ keratomileusis for the correction of high myopia in Meesmann corneal dystrophy: a case report.

The patient was a 26-year-old woman who had manifest refraction and uncorrected and corrected distance visual acuities of -7.00 × -4.50 at 175°, 20/400, and 20/25, respectively, in the right eye, and -3.25 × -5.25 at 179°, 20/200, and 20/25, respectively, in the left eye. In the right and left eyes, the mean corneal thicknesses were 733 and 749 µm, and the maximum epithelial thicknesses were 70 and 68 µm, respectively. Myriads of intraepithelial cysts were observed in the slit-lamp examination. At 30 months after femtosecond laser-assisted laser in situ keratomileusis (femto-LASIK), the manifest refraction and uncorrected and corrected distance visual acuities were respectively 0.00 × -1.25 at 55°, 20/25, and 20/20 in right eye, and 0.00 × -0.50 at 135°, 20/20, and 20/20 in the left eye. In this case of Meesmann dystrophy, myopia was successfully treated with thick flap femto-LASIK without complications or ectasia.

Effects of Subcutaneous Repository Corticotropin Gel Injection on Regulatory T Cell Population in Noninfectious Retinal Vasculitis.

AIM: To evaluate the effect of repository corticotropin injection (RCI) on regulatory T cell population in patients with noninfectious retinal vasculitis. PATIENTS AND METHODS: Patients with active noninfectious retinal vasculitis were included in a prospective nonrandomized open-label study. RESULTS: Eighteen patients (33 eyes) were included in the study. Eleven (61.1%) patients [20 (60.6%) eyes] and 7 (38.9%) patients [13 (33.3%) eyes] were in the responsive and non-responsive groups, respectively. We did not find any statistically significant difference within the PPP-R group, within the PPP-NR group, or between these two groups in regard to regulatory T cell population. No significant systemic or ocular complications were found. CONCLUSION: RCI may be a complementary treatment in patients with non-infectious retinal vasculitis with or without uveitis. This study did not demonstrate an increase in regulatory T cell population in patients with noninfectious retinal vasculitis.

Late recurrence in birdshot chorioretinopathy.

OBJECTIVE: To compare the demographic, clinical, ancillary testing, and multimodal imaging characteristics of birdshot chorioretinopathy (BSCR) patients with late recurrence and birdshot patients with durable remission. PATIENTS AND METHODS: This was a retrospective observational case series. The above-mentioned parameters were studied in BSCR patients with late recurrence (group 1) and BSCR patients with durable remission (group 2). RESULTS: Fifty-five patients were included in this study. The average age of patients was 62.1 ± 11.1 years (range, 35-88 years). Groups 1 and 2 included 20 (36.4%) and 35 (63.6%) patients, respectively. In group 1, the average age of patients was 60.5 ± 10.39 years (range, 35-79 years). The female-to-male ratio was 16:4. In group 2, the average age of patients was 63.1 ± 11.6 years (range, 37-88 years). The female-to-male ratio was 22:13. None of the demographic, clinical, ancillary testing, and multimodal imaging parameters were statistically significantly different between the two groups. Using a receiver operating characteristics (ROC) curve, we found that the ideal duration of successful therapy to induce durable remission was 30 months with 70% sensitivity and 40% specificity (ideal point on the curve). A Kaplan-Meier survival curve demonstrated that late recurrence was seen within 30 months after stopping successful treatment of patients with BSCR. CONCLUSION: There are no demographic, clinical, ancillary testing, or multimodal imaging characteristics that can predict late recurrence in BSCR patients. However, we found that 30 months of successful treatment may be ideal and recommended.

Birdshot Chorioretinopathy: Resistant versus Responsive.

PURPOSE: To search findings that can explain the heterogeneity between Resistant and Responsive patients with birdshot chorioretinopathy. PATIENTS AND METHODS: This was a retrospective observational case series on "Responsive" versus "Resistant" birdshot chorioretinopathy. RESULTS: One-hundred-eighty and Ninety-nine patients were included in the Responsive and Resistant groups respectively. Multivariate analysis of paraclinical variables at the first visit demonstrated that mean deviation (p = .04), pattern standard deviation (p < .001), optic nerve head leakage (p = .012), large vessel leakage and staining (p = .01), and macular small vessel leakage (p = .03) were statistically significantly different between the two groups; however, at the visit preceding successful therapy, only macular small vessel leakage (p = .01) was statistically significantly different between the two groups. CONCLUSION: .Small vessel leakage in the macular area and/or optic nerve head leakage at the earliest visit might be risk factors for resistant birdshot chorioretinopathy.

Optimized Artificial Intelligence for Enhanced Ectasia Detection Using Scheimpflug-Based Corneal Tomography and Biomechanical Data.

PURPOSE: To optimize artificial intelligence (AI) algorithms to integrate Scheimpflug-based corneal tomography and biomechanics to enhance ectasia detection. DESIGN: Multicenter cross-sectional case-control retrospective study. METHODS: A total of 3886 unoperated eyes from 3412 patients had Pentacam and Corvis ST (Oculus Optikgeräte GmbH) examinations. The database included 1 eye randomly selected from 1680 normal patients (N) and from 1181 "bilateral" keratoconus (KC) patients, along with 551 normal topography eyes from patients with very asymmetric ectasia (VAE-NT), and their 474 unoperated ectatic (VAE-E) eyes. The current TBIv1 (tomographic-biomechanical index) was tested, and an optimized AI algorithm was developed for augmenting accuracy. RESULTS: The area under the receiver operating characteristic curve (AUC) of the TBIv1 for discriminating clinical ectasia (KC and VAE-E) was 0.999 (98.5% sensitivity; 98.6% specificity [cutoff: 0.5]), and for VAE-NT, 0.899 (76% sensitivity; 89.1% specificity [cutoff: 0.29]). A novel random forest algorithm (TBIv2), developed with 18 features in 156 trees using 10-fold cross-validation, had a significantly higher AUC (0.945; DeLong, P < .0001) for detecting VAE-NT (84.4% sensitivity and 90.1% specificity; cutoff: 0.43; DeLong, P < .0001) and a similar AUC for clinical ectasia (0.999; DeLong, P = .818; 98.7% sensitivity; 99.2% specificity [cutoff: 0.8]). Considering all cases, the TBIv2 had a higher AUC (0.985) than TBIv1 (0.974; DeLong, P < .0001). CONCLUSIONS: AI optimization to integrate Scheimpflug-based corneal tomography and biomechanical assessments augments accuracy for ectasia detection, characterizing ectasia susceptibility in the diverse VAE-NT group. Some patients with VAE may have true unilateral ectasia. Machine learning considering additional data, including epithelial thickness or other parameters from multimodal refractive imaging, will continuously enhance accuracy. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Long-Term Results of Laser In Situ Keratomileusis in Myopic Patients with Topographic Indices outside Suggested Ranges.

INTRODUCTION: To investigate the long-term results of laser in situ keratomileusis (LASIK) in patients with one or more topographic indices outside the suggested range preoperatively. METHODS: Patients who had conventional or femtosecond laser-assisted LASIK for myopia correction between 2011 and 2015, and had at least one preoperative corneal topographic index outside the suggested range were contacted for a follow-up examination. Ranges were based on the cutoffs suggested for subclinical keratoconus: thinnest pachymetry (TP) < 497.50 µm, maximum keratometry (Kmax) > 47.20 D, maximum 8 mm best-fit-sphere anterior elevation (MaxAE) > 9.50 µm, maximum 8 mm best-fit-sphere posterior elevation (MaxPE) > 20.50 µm, and Belin/Ambrósio enhanced ectasia display-total deviation (BAD-D) > 1.60. RESULTS: Two hundred thirty patients (377 eyes) were enrolled; their mean age at baseline and at follow-up was 30.78 ± 8.16 and 9.06 ± 1.91 years, respectively. Mean ± SD was 484.36 ± 11.49 for TP (n = 133), 48.17 ± 0.83 for Kmax (n = 133), 16.33 ± 5.39 for MaxAE (n = 35), 27.87 ± 7.86 for MaxPE (n = 34), and 1.97 ± 0.36 for BAD-D (n = 162). Post-LASIK and suspected ectasia was found in one (0.26%) and two (0.53%) eyes, respectively. In the remaining 374, the efficacy and safety indices were 0.96 ± 0.14 and 1.01 ± 0.08, respectively. Uncorrected distance visual acuity (UDVA) was not reduced in any eyes, and corrected distance visual acuity (CDVA) was reduced one line in 1.9% of the cases; 79.9% of the cases were emmetropic. The long-term changes in UDVA, CDVA, and spherical equivalent were not different between groups with one, two, or three out-of-range topographic indices (all P > 0.05). CONCLUSION: A single out-of-range topographic index is not a strong predictor for postoperative complications, and one should consider the combination of topographic and clinical findings, or the pattern they create in tandem. Developing a scoring system that would take a combination of indices and topographic patterns may help improve the predictive accuracy of these indices.

Corneal characteristics in Down syndrome patients with normal and keratoconic cornea.

Purpose: To determine the reference range of corneal indices in Down syndrome patients with normal corneas (DS-N) and to compare it with the corneal indices in Down syndrome patients with keratoconic corneas (DS-KC). Methods: A study was conducted using the data of 154 eyes of 154 DS-N and 25 eyes of 25 DS-KC patients. Eighteen indices related to thickness, anterior chamber, keratometry, elevation, and aberrations routinely used for KC diagnosis were extracted from the Pentacam. Results: The mean age of the participants in DS-N and DS-KC groups was 16.73 ± 4.70 and 16.56 ± 4.22 years (P = 0.852). In the DS-N group, 95% CI were 511.65-520.31 for minimum corneal thickness, 2.97-3.07 for anterior chamber depth (ACD), 46.83-47.37 for maximum keratometry (Kmax), 46.13-46.62 for zonal Kmax at 3 mm, 0.35-0.58 for inferior-superior asymmetry (I-S value), 1.56-1.88 for Belin/Ambrósio display-total deviation, 8.65-10.79 for best-fit-sphere posterior elevation at the thinnest point, and 0.18-0.22 for corneal vertical coma. The age-related change in I-S value and corneal spherical aberration (SA) was significant (both P < 0.05). There were significant inter-gender differences in 11 indices; the female DS patients had shallower, steeper, more elevated, and more aberrated corneas (all P < 0.05). There were significant differences in all indices except for ACD (P = 0.372) and corneal SA (P = 0.169) between DS-N and DS-KC groups. Conclusion: In DS patients aged 10-30 years, the reference ranges of corneal indices are different from the range reported for non-DS subjects and are close to values reported for mild KC non-DS cases. The normal values are different between DS male and female; hence, sex-specific ranges should be considered for diagnosis of corneal abnormality in DS patients.

Biometry and intraocular power calculation using a swept-source optical coherence tomography: A repeatability and agreement study.

Purpose: To evaluate the repeatability of biometry and intraocular lens (IOL) power using Galilei G6 and to determine the agreement of its measurements with those of IOL Master 700 and IOL Master 500. Methods: Hundred mature cataract eyes were examined twice with Galilei G6 and the results were compared with those of other two devices. Axial length (AL), minimum (K1), maximum (K2), and mean keratometry, anterior chamber depth (ACD), white-to-white (WTW) diameter, lens thickness (LT), and the calculated IOL power were the studied parameters. The correlation coefficient, within-subject standard deviation (Sw), Bland-Altman method, and 95% limits of agreement (LoA) were used for statistical analysis. Results: The intraclass correlation coefficient (ICC) was above 0.9 for all indices, and the LoA ranged from a minimum of 0.08 mm for AL to a maximum of 0.50 D for K1. Sw also ranged between a minimum of 0.02 for AL, ACD, and WTW and a maximum of 0.13 for K1. In the Galilei G6-IOL Master 700 pair, the narrowest and widest LoA were calculated for AL (0.07 mm) and K2 (0.49 D), respectively. In the Galilei G6-IOL Master 500 pair, the narrowest and widest widths of LoA were calculated for AL (0.17 mm) and K2 (0.92 D), respectively. In the first pair, the LoA of IOL power (0.57 D) were the best for Haigis formula and in the second pair, the best agreement (LoA: 0.35 D) was observed for Holladay-1. Conclusion: Galilei G6 provided repeatable biometric measurements. The agreement between biometry and IOL power calculation was better in the Galilei G6-IOL Master 700 pair compared to the Galilei G6-IOL Master 500.

SMILE after DALK to reduce residual refraction: two-year results.

PURPOSE: To determine the two-year results of small incision lenticule extraction (SMILE) for correcting post-keratoplasty myopia and myopic astigmatism. METHODS: In this case-series study, 10 eyes of 10 patients with a 6- to 10-year history of successful deep lamellar keratoplasty (DALK) underwent SMILE using the VisuMax laser platform. Ophthalmologic examinations and visual acuity and refraction measurement were taken pre- and 1, 3, 6, 12, and 24 months postoperatively. The Pentacam and Sirius imaging were done in the first and last follow-up sessions. RESULTS: The mean age of the patients was 39.60 ± 7.86 years. Six subjects were male. Two years after SMILE, the mean improvement in UDVA and CDVA was 3.60 ± 1.84 (P < 0.001) and 1.60 ± 2.91 (P = 0.231) LogMAR, respectively. The mean decrease in spherical equivalent, spherical error, and cylinder power was 1.92 ± 1.96 diopter (D) (P = 0.013), 0.70 ± 3.05D (P = 0.213), and 2.42 ± 2.91D (P = 0.024), respectively. The vector mean target-induced astigmatism, surgical-induced astigmatism, and difference vector were 1.30D@44˚, 1.11D@24˚, and 0.86D@73˚, respectively. Two years after SMILE, vertical coma, horizontal coma, and spherical aberration increased by 0.44 ± 0.51, 0.23 ± 0.32, and 0.02 ± 0.16 µm, respectively, (all P > 0.05) while trefoil reduced by 0.29 ± 0.75 µm (P = 0.428). CONCLUSION: SMILE can be an effective procedure for reducing refraction and astigmatism after DALK in patients with moderate myopia and moderate to severe astigmatism and improves the visual acuity in these patients. Axis rotation during surgery may result in under-correction of astigmatism. Refinement of SMILE treatment nomogram for post-DALK cases seems necessary.

Comparative Contralateral Randomized Clinical Trial of Standard (3 mW/cm2) Versus Accelerated (9 mW/cm2) CXL in Patients With Down Syndrome: 3-Year Results.

PURPOSE: To compare the long-term results of accelerated corneal cross-linking (CXL) (9 mW/cm2, 10 min) with standard CXL (3 mW/cm2, 30 min) in patients with Down syndrome who had keratoconus. METHODS: In this contralateral randomized clinical trial, 27 patients with Down syndrome aged 15.78 ± 2.46 years (range: 10 to 19 years) were enrolled. CXL was performed using the KXL System (Avedro, Inc) under general anesthesia, and patients were followed up for 3 years. The main outcome measure was a change in average keratometry in the 3-mm zone around the steepest point (zonal Kmax-3mm). Secondary outcomes were changes in Corvis ST (Oculus Optikgeräte GmbH) biomechanical parameters and vision, refraction, and corneal tomography measurements. RESULTS: Mean 3-year changes in zonal Kmax-3mm were not significantly different between the accelerated and standard groups (-0.06 ± 0.75 and -0.35 ± 0.94 diopters [D], respectively, P = .727). Despite the contralateral design of the study, based on most baseline biomechanical indices, corneas in the standard group were weaker before treatment. The standard group also showed significantly fewer 3-year changes in the stress-strain index (-0.11 ± 0.21 vs -0.30 ± 0.32), integrated radius (+0.99 ± 3.48 vs +3.14 ± 2.84), and deformation amplitude ratio-2mm (-1.38 ± 1.33 vs +0.30 ± 1.75) (all P < .0167). Corneal stiffness in the accelerated group was stable for 2 years, and the decline mainly occurred during the third year. CONCLUSIONS: In young patients with Down syndrome who had keratoconus, accelerated and standard CXL showed a similar flattening effect. Standard CXL is better able to maintain corneal stiffness in weaker corneas. With accelerated CXL, despite stable results for 2 years, there was decreased corneal stiffness in the third year. Longer follow-up periods are warranted to study the decreased efficacy on keratoconus progression. [J Refract Surg. 2022;38(6):381-388.].

B-Scan Ultrasonography Findings in Unilateral Posterior Scleritis.

Purpose: To evaluate the B-scan ultrasound findings in unilateral posterior scleritis. Methods: This was a retrospective observational case series at a tertiary uveitis clinic. The study population included patients who had been diagnosed with milder forms of unilateral posterior scleritis since 2010 and had B-scan ultrasonography of that eye. The healthy eye of each patient was considered the control eye for that patient. Results: The average age of patients was 50.2 ± 17.8 (range, 18-67). Posterior scleritis was idiopathic in 6 (66.7%) patients and associated with rheumatoid arthritis in two and HLA-B27 ankylosing spondylitis in one patient. The thickness of the thickest area in the diseased eye was 2.08 ± 0.49 (range, 1.35-3.2) and the control eye was 1.53 ± 0.38 (range, 1.03-2.3). The difference between the symptomatic and control eye was statistically significantly different (P = 0.02). 1.7 mm was the cut-off-point on the receiver operating characteristics curve with the highest combined sensitivity and specificity of 87.5% and 88.9%, respectively. Comparing the thickness of the thickest section of the symptomatic eye of one patient with the same section in the other eye of the same patient, there was a difference of 20% or more in sclero-choroidal complex. Conclusions: In this study, the sclero-choroidal complex thickness higher than 1.7 mm has the highest combined sensitivity and specificity. Comparing the thickest section of the symptomatic eye of one patient with the same section in the other eye can be diagnostic.

Best Indicators for Detecting Keratoconus Progression in Children: A Report From the Shahroud Schoolchildren Eye Cohort Study.

PURPOSE: The purpose of this study was to investigate 3-year changes in keratoconus (KC) indices to determine the indicators of KC progression compared with age-related changes in children aged 6 to 12 years. METHODS: In this report of the Shahroud Schoolchildren Eye Cohort Study, KC was diagnosed based on vision, refraction, tomography, and slitlamp examination findings. KC progression was defined as changes in refractive astigmatism or zonal maximum keratometry (Zonal Kmax-3 mm). Then, 3-year changes (Δ) in vision, refraction, and tomographic indices were compared between progressive KC and normal eyes. The best set of ∆parameters for distinguishing KC progression from age-related changes were determined using the area under curve (AUC). RESULTS: Eighteen KC eyes and 10,422 normal eyes were analyzed. All KC cases showed progression after 3 years. Δindices were statistically different between the 2 groups except corrected distance visual acuity, anterior radius of curvature, irregularity index, and KC percentage index. The best Δindices, in descending order of AUC value, were index of height decentration, Zonal Kmax-3 mm, refractive astigmatism, single point Kmax, and index of vertical asymmetry (all AUC > 0.9), followed by inferior-superior asymmetry, index of surface variance, minimum corneal thickness, index of height asymmetry, KC index, posterior radius of curvature, and Belin/Ambrósio total Deviation (AUC = 0.8-0.9). CONCLUSIONS: According to our findings, changes in index of height decentration, Zonal Kmax-3 mm, refractive astigmatism, single point Kmax, and index of vertical asymmetry are the best indices for detecting KC progression in children younger than 12 years.

Comparison of transepithelial and conventional photorefractive keratectomy in myopic and myopic astigmatism patients: a randomized contralateral trial.

BACKGROUND: To assess transepithelial photorefractive keratectomy (tPRK) in terms of corneal epithelial healing rate, postoperative pain, postoperative discomfort, and visual and refraction outcomes compared to mechanical epithelial debridement PRK (mPRK) and alcohol-assisted PRK (aaPRK). METHODS: In this double-masked, randomized clinical trial, thirty-nine patients underwent tPRK in one eye and mPRK in the fellow eye (arm A), and 33 patients underwent tPRK in one eye and aaPRK in the contralateral eye (arm B). All surgical procedures were done using the Schwind Amaris excimer laser. The area of corneal epithelial defect in all eyes was captured and analyzed using ImageJ software. RESULTS: Mean epithelial healing time was respectively 3.74 ± 0.82 and 3.59 ± 0.79 days in tPRK versus mPRK (P = 0.21) in arm A, and 3.67 ± 0.92 and 3.67 ± 0.74 days in tPRK versus aaPRK (P = 1.00) in arm B. Accounting for the initial corneal epithelial defect area, the epithelial healing rate was faster in conventional PRK groups compared to tPRK (both P<0.001) in both arms. However, there was no significant difference in safety, efficacy, spherical equivalent refractive accuracy, or corneal haze development between tPRK and conventional PRK groups (all P > 0.05). CONCLUSIONS: All three methods are effective in terms of visual and refractive outcomes. However, although time to complete re-epithelialization was similar with the three methods, the epithelial healing rate was faster in conventional PRK considering the initial corneal epithelial defect area, and the patients experienced less pain and discomfort in the first postoperative day. TRIAL REGISTRATION: IRCT, IRCT20200317046804N1 . Retrospectively registered 5 May 2020.

Visual functions and disability in Iranian adults: a population-based study.

BACKGROUND: Vision-related quality of life is related to severity of visual impairments and show the impact of eye diseases on daily activities. This study aims to assess visual functions and disability and its association with age, gender, education, marital status, and economic status in adults aged 45-69 years. METHODS: Data in this population-based study were from the second phase of the Shahroud eye cohort study and collected by using a Short-Form Visual Functioning Scale. The scores of visual function and disability were calculated based on Rasch-transformed scores of the National Eye Institute visual functioning questionnaire, where a more negative score indicates a better situation. Multiple linear regression was used to investigate the factors associated with visual functions. RESULTS: Among 4737 participants the visual function data for 4715 people were analyzed. The visual function of 75.3, 17.1 and 7.5% of participants were "ideal and good", "moderate", and "bad and very bad", respectively, while 0.06% were unable for vision. The running mean of the visual function was calculated to be - 3.95 ± 0.02. The visual performance was worse in females than the males (ß = 0.14, p = 0.005). Visual function improved with increasing levels of education (ß = - 1.06, p < 0.001). It was worse in low-economic (ß = 0.016, p = 0.005) and moderate-economic (ß = 0.28, p < 0.001) participants than high-economic ones. CONCLUSION: The visual function of Iranian adults aged 45-69 years was moderate. The male gender, higher education and the higher economic status had a better visual function.